How the Eye Works
The eye is an amazing part of our body that enables us to see and make sense of objects around us. But do you ever wonder about the mechanism behind it all? How the eye works?
When you are looking at an object, there are a few things that occur. First, light reflects off the object and enters your eye. This is when your ability to actually see starts. Since this light is unfocused, the light rays are focused onto your retina, which is the light sensitive layer in your eye.
Once this happens, the cells in your eyes are stimulated by the light to send millions of electrochemical impulses along your optic nerve, to your brain. There is a portion of your brain found at the back of your head that interprets these impulses and that’s basically how you are able to see an object.
What Is the Importance of Light And Refraction?
Refraction is a term used by optometrists to describe the process when light entering your eye is first bent by your cornea, which is a clear window on the outer front surface of your eyeball.
The light is bent the second time after passing the cornea, by a crystalline lens found inside your eye. This happens to provide a more adjusted focus. To be able to focus the light onto the retina, the ciliary muscles in your eye change the shape of the crystalline lens, by either bending or flattening it, a process commonly known as accommodation. When this happens, both far and near objects are brought into focus.
How Do Vision Problems Occur?
There are different vision problems that affect us, all depending on the ability of our eyes to refract light. If an error occurs during the refraction process, what results is either a case of myopia (nearsightedness), hypermetropia (farsightedness) , presbyopia or astigmatism.
Good news is, these conditions can be easily corrected by using prescribed contact lenses or spectacles, which changes the refraction of the eye.
Myopia occurs when light rays from an image occur in front of the retina. When the rays are focused behind the retina, you get hypermetropia and astigmatism will occur when the cornea curvature is irregular, which then causes light rays to focus in multiple places, resulting to a blurred vision.
As people age, performing close up activities such as reading become quite a task. This condition is known as presbyopia, and occurs when the crystalline lens is less flexible which limits its ability to bend light.
How Does The Eye Make Sense of Light?
You are not able to see just from refraction, as the image looks inverted at this point. The eye has receptors, rods and cones, which are cells sensitive to light and located in the retina.
Rods allow us to see even in dim light, and to detect motion, whereas cones enable us to detect colors, and also perform tasks that need a detailed focus such as reading, or seeing far objects.
When the impulses reach the optic nerves at the back of your eye, and are directed to the visual cortex located at the back of your head, they are unscrambled and interpreted. This is the point when the image is re-inverted and you can now see objects in their right form, making it the final seeing process.
Is your vision less than optimum?
An optimum eye vision is described as 20/20 or 25/25, which may not mean having perfect vision, rather, it indicates normal visual clarity.
If you are not sure about your vision or you are experiencing some eye problems, contact your optometrist for a consultation to determine the next course of action.